Theresa Nielsen

Brøndby IF, 2009–2016

In 2012, Eslund was named Danish Women's Footballer of the Year after helping Brøndby IF to a league and cup double.

Vålerenga, 2017

In January 2017, Eslund signed with Norwegian club, Vålerenga in Oslo, marking her first time playing for a foreign club. Eslund made 22 appearances for Vålerenga and scored two goals during the 2017 season. She scored her first goal for Vålerenga in the 47th minute of a match against Kolbotn resulting in a 2–0 win. The club finished in seventh place with a 10–8–4 record. Eslund was named one of the top 200 players in the world for 2017 by The Offside Rule, a podcast by The Guardian.

Reign FC, 2018–2019

Eslund signed with American side Reign FC ahead of the 2018 National Women's Soccer League season in January 2018. She made her debut for Seattle as a starting defender during the home opener — a 2–1 win over the Washington Spirit on 24 March.

Return to Brøndby IF

Eslund returned to Brøndby IF on a two-year contract in 2020, were the team ended up at second place in the league.

At age 17, Eslund competed with the Denmark's under-17 national team at the 2003 European Youth Summer Olympic Festival. She scored in the final as Denmark beat Switzerland on penalties after a 1–1 draw at Stade Sébastien Charléty in Paris. Eslund made her senior international debut for Denmark in March 2008, during the team's 1–0 win over Germany at the 2008 Algarve Cup. She was called up to Kenneth Heiner-Møller's squad for UEFA Women's Euro 2013 and she was also part of Danish squad, who received silver at the UEFA Women's Euro 2017 in Netherlands.

Raised in Valby, Eslund began playing football at age six on a team known as Rikken.

Brøndby IF Elitedivisionen: Winner 2011, 2012, 2013, 2015, 2017 Danish Women's Cup: Winner 2010, 2011, 2012, 2013, 2014, 2015, 2017 Denmark UEFA Women's Euro 2017 runners-up Individual UEFA Women's Euro 2017 Best XI Toppserien Defender of the Year: 2017